Induction vs Gas Cooking

[Dsanduril]

Originally Posted by Adelie

I think limiting short term draws to 0.1C is excessively conservative. Yes there is more voltage drop at 0.2 or 0.3C but not so much that the inverter drops out, unless you are already at 50% DoD, then the problem is not discharge rate.

If you are pulling 1200W and limit current to 0.25C then you will need at least a 400Ah bank. I have a 300Ah bank on my 20' boat.

Comparisons to a windlass are misleading. A windlass is going to be at the end of a long run of cable with significant voltage drop just for the distance. The inverter should be positioned as close to the battery as possible to minimize voltage drop for this reason.

100A coming out of the battery is 100A coming out of the battery - the battery doesn’t care about the distance to the load. With a windlass you pull that load in generally pretty short bursts, and for a relatively short time (even pulling up all 100m of our chain takes 5 minutes or less). An induction hob on high can draw that same amount for a lot longer. As Dockhead notes, it doesn’t always have to be on high, but if you want that pot of pasta water to boil quickly

[Seaworthy Lass]

Originally Posted by Auspicious

Jeepers. I posted a long response to everyone except Seaworthy Lass which I opened by saying her post required more thought than my break from billable work allowed. I came back tonight to follow up and find that something happened to that post. Now I’ll have to reconstruct that.

Ladies first.

Thank you sir. I love a good debate .

Originally Posted by Auspicious

I think you should scroll back and read the thread from the beginning. You might want to look up FMEA as well. Go ahead. We’ll wait. There will be a quiz. *grin*

All 148 posts again? Can I pick another penance? .

As well as “what would you do with a raw chook” if your power source failed and “funny shaped bread is second rate”, the main thrust of your arguments has been the safety issues when using electricity.

I think the failure mode most people are most concerned with when using gas is an unexpected big bang, which would do a bit more than just make you spill your coffee. We fitted gas taking great precautions, but it would be nice to eliminate this risk completely.

There are insufficient users of induction for any reasonable comparisons to be made comparing the safety of gas vs electric cooking, but I would think that if you already had a boat set up to handle high power demands (necessary if using electricity to cook with exclusively all year around) then plugging in an induction hotplate poses only a minuscule additional risk.

To minimise this minuscule risk you could select a reputable brand, replace it frequently (it is cheap enough to even do this six monthly if you were paranoid), unplug it when not in use ......

In my view this is far, far safer than using gas, both from the explosion and naked flame perspectives.

The big reason this brilliant means of cooking is not used by most small yachts full time is that they simply do not want to be running a generator to do so.

Originally Posted by Auspicious

Why is a dinghy ride not sufficient? Are your tanks fixed to the boat? A full 12 kg tanks is lighter than a full Jerry jug of water.

The 12 kg relates to the weight of the gas, the tanks are additional.
The total weight of a full 12 kg gas tank can be around double this, depending on the material used.

Now I don’t know about you, but carrying 25 kg in any more than a few metre hops over a short distance defeats me (and not just because of my lack of meat consumption ). I have only rarely found gas close to where I could land our dinghy. For safety reasons taxis won’t transport gas bottles, nor can they be taken on public transport. Car hire is the only option. Replacing a gas cylinder then becomes an all day job if a car hire place needs to be found.
We are not cruising populated areas in the US, nor are we hopping between harbours, so gas replacement has definitely NOT been easy for us. It is a royal PITA.

Originally Posted by Auspicious

With even moderately good ventilation humidity from the products of combustion does not compete with the humidity from cooking itself. Steam from boiling pasta water (sshhh – don’t tell Dockhead – he abhors the stuff), rice, soups, even stews. Let’s not forget that a huge source of humidity on board is people breathing. We’re really horrible sources of humidity. The real challenge is thermal conductivity of mountings for hatches and portlights. The metal gets cold and falls below the dew point. Condensation happens. That can be managed. First and most important is ventilation. Yes, outside air in high latitudes is cold but it is also dry. This is where forced air diesel heaters shine. You can draw domestic air from outside and heat it rather than recirculate inside air that just gets wetter and wetter. For other substantial heat sources such as diesel hydronic and your Reflex heater you have to provide the ventilation yourself. I’m not suggesting throwing open the boat. You don’t need that much make-up air. There are technical references for this in the HVAC-R community. I posted a specific reference to a lay publication above.

Now here I seriously beg to differ, simply as I have experienced the direct contrast of wintering in Scotland twice, once using gas for almost all the cooking and once no gas at all when the hotplate of the Refleks heater was used. The contrast in moisture production was dramatic. Enough so that it far outweighed the moisture produced by cooking itself and heavy breathing (and there is a fair bit of that going on in winter months ). The moisture from this can be very easily handled with just good ventilation, which we have.

I admit it does depend on how you cook though.
I frequently simmer soups and stews (both generally with pulses that require longer cooking times), but I use a pressure cooker with an excellent seal on the lid, even if I am not bringing the contents to pressure. I put lids on all other pots. I rarely have pots of water simply boiling as I don’t want a boat full of steam.

Baking bread, pizza, cakes, biscuits and scones (translation: cookies and something that is akin to Southern biscuits) in a frypan with the lid on produces almost no moisture compared to operating a gas oven. The difference is HUGE. I repeat HUGE. Enough so that I am thrilled to eat funny looking bread and thinner cakes that taste equally delicious to their oven baked counterparts. The pizza is actually superior with the crusty bottom you generally only get with wood fired ovens or pizza stones that have been heating for an extended time.

Originally Posted by Auspicious

I could use some numbers here for how in high latitudes you can run an induction hob for hours on end off solar at low angles for only a few hours per day. How much solar do you have?

Our induction hotplate could not be run at all over the winter months here. The Refleks was used exclusively then (and yes, temperature control was a challenge, but I enjoy challenges).
We have 1005 watts of solar and rely on this almost exclusively (the engine’s alternator usually only contributes when we leave or enter an anchorage). We have no generator.

At 57° N at the solstice the sun angle at its peak was around 13° and daylight hours were around 6.5. The bonus is that the light was superb for photography. Conditions were akin to dawn or dusk all day .

SWL

“Baking” sweet rolls in a frypan on a hotplate:

[CatNewBee]

What I can tell in the 3rd year of electric cooking is, fridges and freezer chew up similar or often more power (Battery Ah) than the induction hobs and convection oven during the day.

We cook our meals traditionally from fresh stuff, no pre-processed convenience food in the microwave (we dont even have one any more on board) . We use often 3 burners at the same time or the oven, we do deep freeze and store bread and bake it up in the morning for 15 minutes at 200°C for breakfast and we use a real espresso machine for fresh grinded coffee. We cook at least one hot meal per day usually. We use the galley as we used our kittchen at home.

All this on solar only.

You need a good and properly sized installation to do this, we consider our setup as minimal requirement to do it the way we do (1650Wp solar, 1000Ah LiFeYPO4, 5kVA inverter). More would be better.

[StuM]

Originally Posted by Seaworthy Lass

“Baking” sweet rolls in a frypan on a hotplate:

Looks good.Is the recipe in the "mostly plant based" thread?

[Dockhead]

Originally Posted by Auspicious

. . . Not really. On gas heat is generated by combustion and heats pan and air by conduction, convection, and radiation. The hot pan and food also heats air by conduction and radiation (I think convection is de minimis). Induction heats the pan and the pan heats food and surrounding air. Secondary heat reduces the efficiency differential between gas and induction.

That sounds reasonable. Except -- you forget the stream of hot combustion products. But efficiency of gas in getting heat into the food is not important. Gas has a killer efficiency advantage in that combustion is being used directly instead of converted to electrical power and back to heat. Gas wins hands down on this; the bottle of gas is worth probably several times its weight in diesel fuel used to generate electricity to cook with. I was not claiming that induction is more efficient than gas other than wasting less heat; I was claiming that in practical real life it is several times more efficient than electric resistance heating. Not in the case of boiling a pot of water from cold, but with smaller heat and non-ideal sized pans -- average use. This is reflected in far less heat going into the cabin. That is not an advantage in my latitude, just an observation. The only point I was making is that induction cooking uses far less power from your batteries than you are assuming.

The illustrative case is simmering. You simmer with resistive heat, you are only using a tiny amount of power in the food, but there is a stream of hot air rising up around the pan. I guess the lower and lower the heat, the smaller proportion goes into the food. With induction, you are only using just that amount of power which goes into the food (less a little radiated from the pan as you point out, but this is a little).

I'll try to measure this today and give figures. I don't want to cut open a cord to put an ammeter on it, but I can shut down everything on my ring main and use the fixed ammeter.

Originally Posted by Auspicious

I had a long train of reasoning first time around. You’re going to need footnotes for that assertion. I simply don’t believe it. With real-life pans you’ll have many more losses and radiation.

Well, on resistive heat, the heat pours out around pans which are not precisely fitted to the burner. That is the point, and it is really like that. It makes a big difference in how much electrical power is used for a given cooking task, induction vs resistive. I know this from experience, having used a good halogen resistive hot plate for cooking for years on board before I got the induction. The resistive hot plate would flatten the batteries more or less like how you calculated. You can do the same task for about 1/3 the power, roughly, with induction. That's practical experience, an observation.

Originally Posted by Auspicious

By the way, we haven’t talked about the famous induction buzz of cookware. Bonding of disparate materials is critical and you need to buy rather expensive cookwareto avoid the buzz.

I've not had this issue. I inherited a set of expensive Cristel cookware from the PO of my boat; it works fine. I bought a couple of specific induction pans to supplement. It all works great and no buzz. YMMV. But I guess any pan which was designed for induction, and most these days are, will not have problems.

Originally Posted by Auspicious

. . . I have friends who are professional chefs. They crew for me. I fill in for them when they need someone they can depend on. I ran an omelet station at a breakfast buffet with a couple of catering gas burners and an induction hob. I did not see anything like the time differential you speak of side-by-side. Catering burners by the way are cheaper than induction hobs. *grin*

A big gas burner I'm sure will heat up a pan as fast as induction. A big gas burner can be a lot more than 2000 watts. I was comparing to the burners on boat stoves, which are far weaker. The difference is huge.

Originally Posted by Auspicious

The thermal mass of the two is the same, absent the little metal grate on a gas cooker. Maintaining a simmer isn’t a problem for most people either way. For many the UI of induction slows things down.

Sure -- that wasn't a comparison to gas. As to maintaining a simmer -- that was always a problem for me my whole life until I started using induction. Even on my weak gas stove on the boat. I would often put another pan between the pan with the food, to moderate (i.e. waste) some heat. And since you don't control temperature, even if you get the right amount of heat, you still have the risk of burning the food a little on the bottom. It's hard to describe how brilliant induction is for simmering. Because it allows control of temperature as well as volume of heat.

Originally Posted by Auspicious

Risk doesn’t work that way. Subsidiary risk is not additive. It increases the total risk but not by addition. I don’t remember the math but I can look it up. I do remember that the lower the subsidiary risk the smaller the portion that gets aggregated. Quantitative risk assessment is not my specialty. I’ve had such people work for me in the past.

I would like to understand how that works. Why is this a "subsidiary risk"? Risk from a gas system stands alone. If you have gas -- you have that quantum of risk. You don't have gas, then you don't. It has nothing to do with the other risks, which I believe is the very point you were making, except that I believe it works the opposite way you are saying. I'd like to be enlightened here if I don't understand something. I believe it works just like driving or not driving. I go out in my car today -- I have x risk of having a road accident. I stay home today -- I have 0 risk of having a road accident. Difference is -x. Gas on board -- you have x risk of blowing the boat up. No gas on board -- 0 risk of blowing the boat up. Difference -- -x. Ne c'est pas?


By the way, you kept talking about fire. The risk with gas is not fire, it's explosion. LPG is almost twice as heavy as air. Released in air it behaves like a liquid and flows down into your bilge and hangs out, because it can't drain out anywhere (that's why it is far more dangerous on a boat than on land). LPG has a wide range of explosive mixture with air, and a spark will do it. Doesn't happen that often, for sure it's a risk you can kind of live with, but someone is killed or maimed on a regular basis. It may be that boat electrical fires are more frequent, but how many are fatal? My down and dirty research showed, for the UK, the big killers/maimers were MOB, head split open by the boom, gas explosion, petrol/gasoline explosion (usually motorboats at the fuel dock), asphyxiation. A death here and there from collision (Shoreway accident). Don't recall any deaths from electrical fires.


I did this down and dirty because actual statistics meaningful to us are hard to find. "Boating" statistics relate 90% to small boats used on lakes and very different from our use case. The U.S. "boating" accident statistics don't differentiate fire from explosion.


Here are just 6 years of incidents in the UK alone:


"2004 A fire and explosion was caused when the crew of a boat were changing gas cylinders with candles alight in the cabin. The vessel was declared a total loss.
2005 The deck of a 22ft sloop, berthed in Emsworth, West Sussex, was blown off and the owner later died in hospital. Multiple explosions were caused by gas and an outboard petrol tank that ignited.
2005 A fire on a sailing yacht on passage for three days was thought to have been caused by a gas leak. A gas detector on board had not gone off during the incident. Two crew abandoned ship and were rescued from their liferaft.
2006 A suspected gas leak on a motorboat in Brighton Marina resulted in the owner suffering serious burns.
2007 An explosion on a boat in Scotland was caused by a leak in the gas pipework to the stove. Two crew suffering burns had to swim ashore. One died later in hospital.
2007 A gas explosion on a boat in Norfolk was thought to be caused by a loose gas hose
on the cooker ignited by a spark from an electric bilge pump or fridge compressor.
2008 A sailing boat in Pwllheli was declared a total loss following an explosion while the boat was moored in the harbour. The source of ignition was thought to be a Calor gas powered refrigerator. The owner was badly burned but his wife was luckily sitting in the cockpit. Both were taken to hospital.
2010 A Cornish Shrimper on the Norfolk Broads suffered a small explosion when a camping stove being used in the cockpit was not properly turned off after boiling a kettle. The accumulated gas leak caused an explosion and minor burns to the crew."

Probably not a complete list. From: https://www.yachtingmonthly.com/sail...xplosion-29779


This is what an LPG explosion on a boat looks like:

https://www.youtube.com/watch?v=vuLIM7NakUI

[Seaworthy Lass]

Originally Posted by StuM

Looks good.Is the recipe in the "mostly plant based" thread?

Hi Stu
No, it contains butter and eggs and I have been crucified for posting recipes there that contain ingredients that animals have even looked at let alone contributed to so it wasn’t included. It was actually a slight variation of LostBiker’s mother’s Old Polish recipe.

The recipe was in the frypan “baking” on a Refleks diesel heater thread:

https://www.cruisersforum.com/forums...er-226591.html

I make a very close vegan substitute using a sweet version of Oatmeal bread, which was a modified version of a recipe originally given by Beth Leonard. That has a similar texture and is in the plant based recipes thread. It is scrumptious with the addition of orange rind and cardamom.

SWL

[Dockhead]

Originally Posted by CatNewBee

What I can tell in the 3rd year of electric cooking is, fridges and freezer chew up similar or often more power (Battery Ah) than the induction hobs and convection oven during the day.

We cook our meals traditionally from fresh stuff, no pre-processed convenience food in the microwave (we dont even have one any more on board) . We use often 3 burners at the same time or the oven, we do deep freeze and store bread and bake it up in the morning for 15 minutes at 200°C for breakfast and we use a real espresso machine for fresh grinded coffee. We cook at least one hot meal per day usually. We use the galley as we used our kittchen at home.

All this on solar only.

You need a good and properly sized installation to do this, we consider our setup as minimal requirement to do it the way we do (1650Wp solar, 1000Ah LiFeYPO4, 5kVA inverter). More would be better.

Great, real life experience


Do you have numbers on daily AH used for cooking?

[StuM]

Originally Posted by Seaworthy Lass

Hi Stu
The recipe was in the frypan “baking” on a Refleks diesel heater thread:

https://www.cruisersforum.com/forums...er-226591.html

Darn it, I've never looked at that thread because of the title.


Now I see the first post says:
"Given the surge in induction cooking, this technique could also probably be successfully adopted."

So, as a keen user of induction, I'm now heading off to read the other 80 posts in that thread

[Seaworthy Lass]

Originally Posted by StuM

Darn it, I've never looked at that thread because of the title.


Now I see the first post says:
"Given the surge in induction cooking, this technique could also probably be successfully adopted."

So, as a keen user of induction, I'm now heading off to read the other 80 posts in that thread

There did not seem to be much interest in the technique so I did not persist with posting.

I will go and alter the title name.

When I started the thread last November I did not have enough solar power to use the induction hotplate and only speculated that it would work for “frypan baking”, but I have had nearly two months doing this now and I can report the technique works even better, as I now have good temperature control. I think it would work equally well on any stovetop including gas and metho, although cooking times will vary. This makes it valuable for anyone without an oven.

It did take a lot of experimenting to get the hang of it. I tried using a pressure cooker pot (with no seal) the year before with some truly spectacular failures and I gave up that season. Thankfully I persisted, as a hotplate can be used with great success. I am now totally hooked .

The gas has been turned off at the bottle for seven months now.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

. . . The gas has been turned off at the bottle for seven months now. . .

Gasaholics anonymous . . . .


Do you have a gas oven?


I rarely use mine. I don't bake bread and there are few baked things in my cooking repertoire. I have, however, had people on board who baked a lot, and I go through gas really fast when that happens. The oven uses a ton of gas compared to the cooktop. Someone of my crew did bake bread when we were in the Arctic, but I didn't like the product. I have narrow tastes in bread.



I have an electric countertop oven I use rarely, a kind of "toaster oven". It's not that useful, but when gas is running low and I have someone on board who must bake something, it can be handy. What I really need to do is replace the built-in large microwave with a built-in micro/convection. I've been using convection ovens in my land homes for decades by now; it's a leap forward similar to induction over gas on the cooktop. Would be great to have on the boat.

[Seaworthy Lass]

Originally Posted by Dockhead

Gasaholics anonymous . . . .


Do you have a gas oven?


I rarely use mine. I don't bake bread and there are few baked things in my cooking repertoire. I have, however, had people on board who baked a lot, and I go through gas really fast when that happens. The oven uses a ton of gas compared to the cooktop. Someone of my crew did bake bread when we were in the Arctic, but I didn't like the product. I have narrow tastes in bread.

I have an electric countertop oven I use rarely, a kind of "toaster oven". It's not that useful, but when gas is running low and I have someone on board who must bake something, it can be handy. What I really need to do is replace the built-in large microwave with a built-in micro/convection. I've been using convection ovens in my land homes for decades by now; it's a leap forward similar to induction over gas on the cooktop. Would be great to have on the boat.

I have not just an oven, but “le roi” of boat gas ovens . It is a GN Espace.

It is well insulated and cooks very evenly. When I was using it daily I would have said it was worth every penny. The top now makes a good gimballed surface for the induction cooktop .

At home I used a convection oven and a seperate microwave. Now that I know how much excess solar power we have for seven months of the year at this latitude, I am tempted to buy a microwave, but I would not bother combining it with a convection oven. The frypan works well for all my baking needs.

This is our oven (the second photo taken by a photographer commissioned by KM shows the general layout):

[Dockhead]

Originally Posted by Seaworthy Lass

I have not just an oven, but “le roi” of boat gas ovens . It is a GN Espace.

It is well insulated and cooks very evenly. When I was using it daily I would have said it was worth every penny. The top now makes a good gimballed surface for the induction cooktop .

At home I used a convection oven and a seperate microwave. Now that I know how much excess solar power we have for seven months of the year at this latitude, I am tempted to buy a microwave, but I would not bother combining it with a convection oven. The frypan works well for all my baking needs.

This is our oven (the second photo taken by a photographer commissioned by KM shows the general layout):

Wow, that looks beautiful


Mine is a SMEV. Poorly insulated I guess because it uses a lot of gas and doesn't get very hot. It is a jumbo size compared to what I had on previous boats, but the 4 burners are too close together to put 4 normal size pans on it. In fact it's hard to put many pans on it in such a way that you can get a burner under the middle of it.


I can't believe you don't have a microwave. I use mine more than any other cooking device. I find it incredibly useful. How do you reheat leftovers or pre-prepared food without a micro? How do you defrost frozen stuff? Mine has a grill in it -- also very useful. I couldn't live without it. We had a micro on the last boat, too, in a galley less than half the size of this one.

[Seaworthy Lass]

Originally Posted by Dockhead

I can't believe you don't have a microwave. I use mine more than any other cooking device. I find it incredibly useful. How do you reheat leftovers or pre-prepared food without a micro?

This is heated simply in a covered frypan or pot on the Refleks or induction hotplate or gas burner. I make soups and stews in batches and seal this while piping hot in glass jars (a short term form of “preservation”) and refrigerate the jars until needed. The flavour of these dishes tends to improve even further with time. I find this reheated food is actually even better than when freshly made so I use this technique a lot.
I agree a microwave would be very handy for reheating this. I am just undecided if the additional space a microwave occupies is worthwhile. I like the simplicity of not over complicating what we have on board.

Originally Posted by Dockhead

How do you defrost frozen stuff?

Not an issue, as I have no freezer on board .

Originally Posted by Dockhead

I couldn't live without it. We had a micro on the last boat, too, in a galley less than half the size of this one.

You would be surprised how easy it is to adapt to different methods or devices if you can let go of the notion that it is always best to stick to what you have found to work well in the past.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

. . . You would be surprised how easy it is to adapt to different methods or devices if you can let go of the notion that it is always best to stick to what you have found to work well in the past.. .

True. But on the other hand, the accumulated memory of what we found to work well in the past is kind of what we call "skill", isn't it?


In my misspent youth, I cooked for weeks at a time with nothing other than a single Primus stove. Naturally it's posslible to get the job done with a variety of different combinations of techniques and devices, or absence of them.


I like my separate freezer, but it is the biggest electrical consumer on board in terms of AH per day. It uses a ton of power. But having a bunch of frozen vegetables hugely increases autonomy. I would have definitely died of scurvy in the Arctic without that freezer, and would be a life saver on an ocean crossing, too. I would have one on the next boat, maybe two (a big one for long periods off grid, which would be shut down otherwise, plus a small every day one). With the best possible insulation, not like what I have now.


"Can't live without a microwave" is obviously not literally true, for the reasons you stated. But I wouldn't want to be without. One of the most useful devices on board. It's especially good when you're alone on board and need to heat a single portion of pre-made soup or stew or leftover something.



A microwave even saves water, because you don't use a pan which needs to be washed.

[Seaworthy Lass]

Originally Posted by Dockhead

I like my separate freezer, but it is the biggest electrical consumer on board in terms of AH per day. It uses a ton of power. But having a bunch of frozen vegetables hugely increases autonomy. I would have definitely died of scurvy in the Arctic without that freezer, and would be a life saver on an ocean crossing, too. I would have one on the next boat, maybe two (a big one for long periods off grid, which would be shut down otherwise, plus a small every day one). With the best possible insulation, not like what I have now.

We are planning to purchase a second portable fridge before we eventually cross the Atlantic and Pacific, and to install this as a freezer (or second fridge) in the lazarette. It just hasn’t been needed yet in northern Europe.

Originally Posted by Dockhead

A microwave even saves water, because you don't use a pan which needs to be washed.

And saves time taken washing as well! Not my favourite occupation .

Hmmmmm, you may have me convinced. I now need to beg for a little room on the long bench top of the adjacent technical workshop. That is where the architect suggested installing a microwave (much to Noelex’s dismay ) when I was debating where to leave room for one in the galley.

SWL